(Editor’s note: The following commentary originally appeared in the Detroit Free Press on Oct. 21, 2013.)

The Michigan Department of Education has effectively given Detroit Public Schools’ Thirkell Elementary an F.

This is despite news that Thirkell received a B+ from Excellent Schools Detroit’s School Scorecard, that U.S. Secretary of Education Arne Duncan recently said he was encouraged by the work going on there and other Education Achievement Authority schools, and that Thirkell was the top-scoring school in the state on the Mackinac Center’s elementary and middle school report card.

While Thirkell has amassed accolades, the state’s opinion is the only one that matters. The Michigan Department of Education’s Top-to-Bottom list, a statewide ranking that purports to measure school quality, comes with consequences for low-ranked schools. Under law, low-scoring schools may face mandatory principal dismissal or the threat of school closure, among other things. Recently, state legislators have even considered using the list to identify schools for state takeover.

If the Top-to-Bottom list provided an accurate measure of quality, severe consequences might be warranted. But unfortunately, the Top-to-Bottom list appears to measure student poverty rather than school quality.

Education officials have raised this concern. Even the MDE, in its release of the Top-to-Bottom list, published information showing that, as the percentage of students in poverty increased, school Top-to-Bottom scores decreased severely.

It is somewhat expected that a school ranking system that includes student academic performance would be strongly correlated to student poverty. Research has shown for decades that schools that serve larger populations of students from disadvantaged backgrounds tend to post lower test scores. After all, these schools are serving struggling families.

The state might argue that it isn’t fair to criticize the Top-to-Bottom list for its strong correlation to student poverty precisely because of this relationship. Yet, well-respected educational organizations consider this relationship seriously: Grand Valley State University, Michigan’s highest-rated charter school authorizer, accounts for student socioeconomic background when assessing school performance.

The Top-to-Bottom list is what the state uses to send a signal to schools that are performing poorly and to recognize schools that are posting impressive results.

Because the Top-to-Bottom list doesn’t take student poverty into account, the state’s ranking is likely sending some schools the wrong signal. The state may end up penalizing schools — such as Thirkell — that enroll a large population of disadvantaged students.

According to our most recent study, there’s proof that a better ranking system is possible under existing federal requirements. As part of our study, we examined the relationship between student poverty and school rankings in seven other states. The school ranking systems in those states all had a less strong relationship to student poverty than Michigan. Our review of state ranking system methodologies shows many of these states incorporate a measure of growth for the lowest-scoring students.

It’s time to take a step back and reconsider how the state ranks schools. A better measurement of school quality could help Michigan identify schools that are failing, instead of those that are simply serving the neediest students.

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Audrey Spalding is director of education policy at the Mackinac Center for Public Policy, a research and educational institute headquartered in Midland, Mich.